Motion detectors are commonly used to detect and indicate attempts to break into a protected area. There are many different types of motion sensors, such as a PIR sensor, a microwave sensor and a dual technology sensor, which is a combination of the former two. The detectors are typically mounted on a ceiling or wall within the protected area. A microwave motion sensor transmits a microwave signal toward a region to be monitored and in the event that movement is detected within the region, the microwave signal is reflected back from such movement and is modulated due to the Doppler Effect. When a signal is reflected from a moving object (target) it is shifted in frequency. The shift in frequency is called the Doppler Effect and the new frequency is directly proportional to the target velocity. A Doppler sensor uses this principle to detect human motion.
When a detector is installed, the detector is tested to ensure that it is functioning properly. Additionally, the detector is calibrated for the protected area.
Currently, for the dual technology motion detector, the microwave motion detector is calibrated by repeatedly adjusting a potentiometer. Specifically, the installer will walk the farthest distance from the detector within the premises to generate a signal, return to the detector, adjust the potentiometer, and walk the furthest distance again. The potentiometer is adjusted to pick up motion at the maximum distance from the detector within the protected area and closer, but not further.
Each installation is different and requires multiple adjustments. This adjustment process is time consuming and cumbersome. Since the process is cumbersome, some installers will often fail to complete the adjustment of the potentiometer for the protected area.
Accordingly, there is a need to be able to calibrate the detector without requiring substantial effort by an installer.